Numerous publications and patents disclose various methods of maintaining or promoting bone-tissue growth. For example, U.S. Pat. No. 5,103,806 to Clinton Rubin describes methods of promoting bone-tissue growth and bone maintenance by the application of relatively high frequency, relatively low level mechanical load to the bone tissue. The preferred frequency mentioned in that patent document is in the range of about 10-50 Hz, and the preferred peak-to-peak level of the mechanical load is sufficient to induce strain on the order of between about 50 and about 500 microstrain. Mechanical loading on bone tissue at strains of this level and induced within the frequency range set forth above can prevent bone loss and enhance new bone formation.
Rubin has also published many articles about the subject. Two pertinent examples are “Transmissibility of 15-Hertz to 35-Hertz Vibrations to the Human Hip and Lumbar Spine: Determining the Physiologic Feasibility of Delivering Low-Level Anabolic Mechanical Stimuli to Skeletal Regions at Greatest Risk of Fracture Because of Osteoporosis”, Clinton Rubin, Malcolm Pope, J. Chris Fritton, Marianne Magnusson, Tommy Hansson, and Kenneth McLeod, Spine 2003; 28:2621-2627, and accessible as bme.sunysb.edu/bme/people/faculty/docs/crubin/2003-Spine-transmissibility.pdf. This study involves experiments to determine the degree to which high-frequency (15-35 Hz) ground-based, whole-body vibration are transmitted to the proximal femur and lumbar vertebrae of the standing human. The objective of the experiments is to establish if extremely low-level (1 g) mechanical stimuli can be efficiently delivered to the axial skeleton of a human. Under sterile conditions and local anesthesia, transcutaneous pins were placed in the spinous process of L4 and the greater trochanter of the femur of six volunteers. Each subject stood on an oscillating platform and data were collected from accelerometers fixed to the pins while a vibration platform provided sinusoidal loading at discrete frequencies from 15 to 35 Hz, with accelerations ranging up to 1 g peak-peak.
With the subjects standing erect, the results of the experiments showed transmissibility at the hip exceeded 100% for loading frequencies less than 20 Hz, indicating a resonance. However, at frequencies more than 25 Hz, transmissibility decreased to approximately 80% at the hip and spine. In relaxed stance, transmissibility decreased to 60%. With 20-degree knee flexion, transmissibility was reduced even further to approximately 30%. A phase-lag reached as high as 70 degrees in the hip and spine signals.
Another publication, “Inhibition of osteopenia by low magnitude, high-frequency mechanical stimuli”, Clinton T. Rubin, Dirk W. Sommerfeldt, Stefan Judex and Yi-Xian Qin, Drug Discovery Today 6:848-858, August 2001, and accessible as bme.sunysb.edu/bme/people/faculty/docs/crubin/2001-DDT-bone-adapt.pdf, discusses the identification of anabolic agents for the treatment of metabolic bone disease. In searching for the osteogenic (bone-producing) constituents within mechanical stimuli, it was determined that high frequency (10-100 Hz) and low magnitude (<10 microstrain) stimuli were capable of augmenting bone mass and morphology, thereby benefiting both bone quantity and quality.
In all of the known prior art, the vibrations have been introduced by having the subject stand on floor-based vibration devices.